New work from the University of Missouri School of Medicine and MU Health Care has determined that not only were younger total knee arthroplasty (TKA) patients much more likely to need revision surgery, but infection and extensor mechanism complications were more common.
The study, “Revision Total Knee Arthroplasty in Young Patients: Higher Early Reoperation and Rerevision,” was published in the August 31, 2020 edition of The Journal of Arthroplasty.
The study investigators reviewed records for 147 patients age 55 and younger and compared that data to records collected for 276 patients between 60 and 75 years old. The research team found that younger patients were twice as likely to undergo revision within two years of their primary procedure and had higher incidence of infection, mechanism complications and five-year failure of the joint. The only significant difference found in comorbidities between the younger and older patient groups was a history of tobacco use.
Lead author James Keeney, M.D., associate professor of orthopedic surgery at the University of Missouri, told OTW, “Knee replacements help hundreds of thousands of patients each year to relieve pain and improve function. Increasing success with knee replacement surgery over the past four decades has resulted in enthusiasm for the procedure, and has resulted in surgeons extending knee replacement surgery for an increasing number of younger patients.”
“Published studies have indicated that the largest growing group of patients undergoing knee replacement surgery are less than 55 years old. We were interested in looking in looking at the results of knee replacement surgery in this population because little has been reported on the outcomes of revision knee replacement in younger patients. Those studies have generally not compared results to a traditional joint replacement aged patient group (traditional age is 60-75 years).”
Multiple Possible Complicating Factors
“There are a variety of factors that may contribute to younger patients having earlier repeat revision operations. These may include higher expectations for knee replacement performance, higher demands placed on the knee replacement, or the presence of mechanical symptoms that they consider undesirable. A higher rate of poor medical health in younger patients may also play a role. One factor that we identified in our younger aged patients was a higher rate of tobacco use (smoking). Smoking places patients at an increased risk of wound healing complications or infection after knee replacement surgery.”
“Another factor can be related to being overweight. Patients who are very overweight (morbidly obese) have a higher risk of injury to the tendons that course over the front of the knee—called the extensor mechanism. A third factor can be related to a healthier healing response and faster development of scar tissue after surgery. Younger patients also have more robust drive for tissue healing after surgery. This combined with increased sensitivity to pain can contribute to them developing stiffness after knee replacement surgery. All of these factors were identified in our study as common reasons for reoperation after revision TKA in younger patients compared with patients who were a decade or two older when they underwent their revision surgeries.”
“The study has helped me to reflect on how we provide care to our patients. I was surprised to see the high number of patients that we have treated who had potentially modifiable risk factors. While we have not always asked our patients to stop smoking before surgery, our study has helped us to recognize the importance of this. It is probably more important for patients undergoing revision knee replacement than it is for patients undergoing a first time knee replacement surgery.”
